The try of mathematics is nice, but flames your brain. You may much faster through using regex "\d+". Please note by this time, that "eq" is not the same than "==" inside of perl! 
sub check
{
my $value="";
if ($_[0]=~ m/\d+/) { $value=$_[0]; print qq~$_[0] is numeric\n~; } el
+se { $value=""; print qq~$_[0] is not numeric\n~; }
return($value);
}

my $in=0815;
my $out=&check($in);

# have phun!

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In reply to Re: validate if output of command is numeric or not by Anonymous Monk
in thread validate if output of command is numeric or not by kaka_2

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